Karl Friedrich Theodor "Fritz" Anneke (January 31, 1818 – December 8, 1872) was a German revolutionary, socialist and newspaper editor.

[1] He emigrated to the United States with his family in 1849 and became a Union Army officer in the American Civil War, and later worked as an entrepreneur and journalist.

He was one of the leading figures of the Communist movement in Cologne, together with his friends Karl Marx, Friedrich Engels, and Moses Hess (later the intellectual father of Zionism and the State of Israel).

Many of Anneke's friends and comrades from the 1849 campaign in Germany had become Union generals, including his own junior adjunct officer Carl Schurz, August Willich, Ludwig Blenker, Franz Sigel, and Gustav Struve.

A son of Fritz, Percy Shelley Anneke, was a local celebrity in Duluth, Minnesota, as co-founder and owner of the famous Fitger Brewing Company, which is now registered as a U.S. National Historic Place.